AVS 46th International Symposium
    Biomaterial Interfaces Group Wednesday Sessions
       Session BI-WeA

Paper BI-WeA4
Separation of Long DNA in a Microfabricated Channel with Submicron Constrictions

Wednesday, October 27, 1999, 3:00 pm, Room 613/614

Session: Biology at the Nanoscale
Presenter: J. Han, Cornell University
Authors: J. Han, Cornell University
H.G. Craighead, Cornell University
Correspondent: Click to Email
Microfabricated fluid channels with submicron constrictions were used to separate long DNA molecules according to their sizes. The channels were fabricated on Si substrate by photolithography and reactive ion etching techniques, followed by an anodic bonding to make a sealed channel. These channels have alternating thick and thin regions, which allows long DNA molecules to relax during the electrophoretic motion.@footnote 1@ Separation was achieved by the difference in the probability for DNA molecules to escape these 'entropic traps'. Many fluorescence-labeled DNA molecules were collected at the first entropic trap, and launched simultaneously to form a band of DNA molecules. After traveling the channel, each DNA species formed a separated band, due to the mobility difference in the channel. The traveling time of the DNA bands through the channel were measured by monitoring the fluorescence intensity at the end of the channel. Several long DNA species (35~160kbps) were separated as bands in this way, typically within 30 minutes, which is significantly lower than pulsed field methods. Several structural parameters, such as the depth or the length of the thin and thick region, were varied to study the effect on the DNA mobility and the length range of molecules that a given device can separate. Once these relevant parameters are characterized, this device could be a fast way to separate DNA molecules and other polymers. @FootnoteText@ @footnote 1@ J. Han and H. G. Craighead, J. Vac. Sci. Tech. A, in publication (1999)